Three-dimensional (3D) video and image transmission systems and 3D television (3D-TV) in particular have gained market acceptance in recent years. In order to present a 3D stereoscopic image to a viewer according to prior art systems, it is necessary to generate at least two separate views, with one intended for the viewer's left eye, and the other intended for the viewer's right eye. Certain prior art 3D-TV systems and methods have been designed to provide compatibility with existing television transmission standards. Examples include frame-compatible packing methods, one of which is described in “Overview of MPEG Standards for 3DTV,” Motorola Corporation, 2010 obtained from http://www.mpegif.org/m4if/bod/Working%20Groups/WP_MPEG_Standards_for—3 DTV.pdf on Aug. 11, 2010, which is incorporated herein by reference in its entirety. If not directly stated, all documents/papers/articles referenced in the specification are herein incorporated by reference in their entirety.
In essence, a frame-compatible packing method operates by packing two stereoscopic views (i.e., the right-eye view and the left-eye view) into a normal-resolution frame, such as in a side-by-side or over-under configuration. While this method certainly permits transmission of 3D TV content over existing channels, unfortunately, a viewer with an older 2D television will see a packed frame that is not viewable without a 3D-TV, or at least a 3D-aware set-top box or TV. Additionally, this prior art method suffers from significant resolution degradation, as half of the resolution per-frame is sacrificed in order to squeeze two stereoscopic frames (i.e., left-eye and right-eye) into one. In addition to resolution degradation, television system operators such as broadcasters, cable, and satellite operators employing this conventional system/method are required to deploy a new set of transponders, increased bandwidth, or additional channels to broadcast 3D-TV in this manner, leading to significant expenses.
Another drawback to the frame-compatible packing transmission method is that the amount of disparity between each eye is fixed at the time of transmission, causing displays of varying sizes at the receiver system to exhibit vastly varying disparities. The end user has very little opportunity to adjust real disparity to compensate for these problems. At best, baseline disparity may be adjusted, in theory, by displacing a left eye presentation relative to the right eye presentation as images are viewed on a 3D-TV. Unfortunately, inter-object disparity cannot be adjusted.
Other methods known in the art address many of the foregoing issues by encoding view-to-view prediction out-of-band, as described in an amendment to the H.264/AVC video compression standard for Multiview Video Coding (i.e., “ISO/IEC 14496-10, Advanced Video Coding, Annex H: Multiview Video Coding”). Many compatibility issues have been ameliorated by encoding a second (or other) view in a bitstream in such a way that an older codec will discard the extra data, thus rendering a single 2D view. Broadcasts encoded this way benefit by not requiring new channels to be allocated; the same channel may be used to transmit 2D and 3D broadcasts. However, like frame-packing methods, the end user has no granular control over disparity at the point of viewing. As before, at best, the viewer could theoretically control baseline disparity, but not real inter-object disparities.
Furthermore, overhead associated with such coding schemes for a stereo broadcast is 25 to 35 percent, and therefore requires significant bandwidth upgrades for operators. Present bandwidth allocation in video distribution of this kind will therefore grow accordingly. Additionally, such overhead costs impose incremental costs on backhaul—for example, the same video channels cannot use the same number of satellite transponders. Another major problem with methods based on H.264/AVC is that it is assumed that the entire infrastructure is built out upon H.264/AVC, which is not the case. Most U.S. domestic video distribution infrastructure is still based upon MPEG2. As such, the transmission of H.264/AVC video requires a major upgrade to broadcast and distribution encoding infrastructure for those still using MPEG2, a very expensive proposition. Further, it requires that operators absorb significant costs associated with upgrading customer-premise equipment to support the new standard for anyone wishing to receive 3D-TV broadcasts, resulting in an additional capital expense that frame-compatible methods do not impose.
Accordingly, what would be desirable, but has not yet been provided, is a system and method for transmitting stereoscopic image data at low or no incremental bandwidth cost, with complete backward compatibility with existing transmission chains, including, but not limited to, MPEG2 encoding and decoding, and for providing a method for a high quality reconstruction of the transmitted stereoscopic image data at a receiver system.